Field of the Invention
This invention relates to an improvement in progressive multi-focal lenses, and more particularly relates to an ophthalmic lens having a so-called progressive refractive surface. In this type of construction a surface refractive power (or index) is progressively increased vertically from an upper portion to a lower portion of the lens, as the line of sight scans from a distant view to a near view, so as to help the control (or accommodation) of the human eyes.